The present invention relates to a light source module provided for scanning a transparent object, and more particularly to a light source module arranged in an image scanning device for scanning a transparent object.
As the scanner is continuously advancing in manufacturing techniques and its price has dropped to a reasonable level, the scanner now has become an indispensable peripheral device for a standard PC. Owing to the rise of the processing speed of a central processing unit (CPU) in a standard PC and the requirement on high scanning quality for a standard PC user, the image scanning device capable of scanning various kinds of objects has already emerged in the scanner market. For example, an image scanning device which can respectively scan a reflective object (such as a textbook) and a transparent object (such as a film).
Referring now to FIG. 1, the flat-bed image scanning device of the prior art is implemented with using a contact image sensor (CIS) module 11 as the image-pickup module. The CIS module 11 underneath the scanning platform 10 is made up of a RGB light source 111, a rod lens 112, and a sensor chip 113 so as to scan a colored reflective object on the scanning platform 10. While the user tends to scan a transparent object with a flat-bed image scanning device, a transparency adapter (TA) 12 must be provided to be arranged in the flat-bed image scanning device in order to provide a penetrative light. Unfortunately, the transparency adapter (TA) 12 is able to provide a monochromatic light only, and thus it can not be applied to scan a colored transparent object.
Accordingly, the applicant tries to develop a light source module arranged in an image scanning device for solving the problems suffered from the prior art.
It is therefore an object of the present invention to provide a light source module arranged in an image scanning device for scanning a transparent object.
In accordance with a first preferred embodiment of the present invention, the image scanning device includes a scanning platform, an image-pickup module such as a contact image sensor (CIS) module, and a light source module. The light source module includes a cover, a monochromatic light source mounted in the cover for emitting a monochromatic light, a tricolor filtering device (i.e. RGB filters) mounted between the monochromatic light source and the scanning platform for filtering off the monochromatic light into three different monochromatic (i.e. R, G, B) lights, a switching mechanism connected to the tricolor filtering device for being controlled to alternately allow one of three different monochromatic lights to be transmitted to the scanning platform for scanning a transparent object, and a transmission mechanism for carrying the monochromatic light source, the tricolor filtering device, and the switching mechanism to move with the image-pickup module for accomplishing the scanning operation to the transparent object.
Preferably, the monochromatic light source is a cold cathode lamp. Moreover, the switching mechanism is implemented with a motor, and the transmission mechanism includes a stepping motor and a guiding rod.
In accordance with a second preferred embodiment of the present invention, the image scanning device includes a scanning platform, an image-pickup module such as a contact image sensor (CIS) module, and a light source module. The light source module includes a cover, a tricolor light source which is a RGB cold cathode lamp or a combination of red LED array, a green LED array, and a blue LED array and mounted in the cover for emitting three different monochromatic (i.e. R, G, B) lights to the scanning platform for scanning a transparent object, a switching mechanism which may be implemented with a controlled multiple-throw, single-pole switch and connected to the tricolor light source for being controlled to alternately allow one of three different monochromatic lights to be transmitted to the scanning platform, and a transmission mechanism for carrying the tricolor light source and the switching mechanism to move with the image-pickup module for accomplishing the scanning operation to the transparent object.
In accordance with a third preferred embodiment of the present invention, the image scanning device includes a scanning platform, an image-pickup module such as a contact image sensor (CIS) module, and a light source module. The light source module includes a cover, three monochromatic light sources, each of which has the same color, e.g. three white cold cathode lamps, and mounted in the cover for emitting a monochromatic light, a tricolor filtering devices (i.e. RGB filters) connected to the three monochromatic light sources for filtering off the monochromatic light into three different monochromatic (i.e. R, G, B) lights, a switching mechanism which may be implemented with a controlled multiple-throw, single-pole switch and connected to the three different monochromatic filtering devices for being controlled to alternately allow one of the three different monochromatic (i.e. R, G, B) lights to be transmitted to the scanning platform for scanning a transparent object, and a transmission mechanism for carrying the three monochromatic light sources, the tricolor filtering devices, and the switching mechanism to move with the image-pickup module for accomplishing the scanning operation to the transparent object.
In accordance with a fourth preferred embodiment of the present invention, the image scanning device includes a scanning platform, an image-pickup module such as a contact image sensor (CIS) module, and a light source module. The light source module includes a cover, three monochromatic light sources, each of which has a different color and mounted in the cover for emitting three different monochromatic lights (i.e. R, G, B) to the scanning platform for scanning a transparent object, three guiding devices, each of which is connected to one end of the three monochromatic light sources for guiding the three different monochromatic lights (i.e. R, G, B) to the scanning platform, a switching mechanism which may be implemented with a controlled multiple-throw, single-pole switch and connected to the three guiding devices for being controlled to alternately allow one of the three different monochromatic lights to be transmitted to the scanning platform, and a transmission mechanism for carrying the three different monochromatic light sources, the three guiding devices, and the switching mechanism to move with the image-pickup module for accomplishing the scanning operation to the transparent object.